Way I see it, simply put it, there are disadvantages and advantages towards fighting with one weapon or two. There's no such rule stating that fighting with a single one is always, undeniably without fail, better. It all depends on alot of factors. Too many for me to think at once and put here. Hope everyone agrees with me where this general principle.
Practice is key to wielding dual weapons by the way. There are patterns and routine to follow, did you know? Like in Chinese martial arts. Trust me at least, I've seen it done alot of times. I used to practice it myself, though I've never done dual weapons before, I had plenty of friends who did. If it's impractical, it wouldn't have survived so long, why not put it simply as that.
I have nothing else do add, this argument is over anyways.